The specific aim of this project is to design, construct, and evaluate in animals an expandable laserprobe for treatment of occlusive coronary and peripheral artery disease.The proposed device provides means for controlled application of heat and pressure to atherosclerotic tissue. The principle of operation involves the transmission of laser energy from source to patient and the rapid conversion of this energy into controlled thermal energy at the distal end of the probe. When brought into contact with occlusive tissue, this probe allows heat to be conducted rapidly to this tissue while maintaining a known pressure on the probe-tissue interface. This results in selective and controlled ablation of occlusive tissue with minimal thermal effect on surrounding tissue.The basic design objective is to create an expandable laserprobe that can be introduced percutaneously and that alone can generate a sufficiently large lumen to permit adequate flow through coronary and peripheral arteries. The proposed laserprobe is expected to allow suitable patients to undergo a minimally invasive procedure for the relief of occlusive vessel disease in the legs and in the heart, resulting in significant reduction in the cost of health care for this ailment.National Heart, Lung, and Blood Institute (NHLBI)